At the present time there has been developing a great interest in the utilization of solar heat for the supply of domestic hot water, and many of these systems are incorporated with an electrical heating system to maintain a satisfactory supply of hot water during periods when there is insufficient solar energy absorbed by the solar heating panel to maintain a satisfactory hot water supply. Also solar/gas storage systems are presently available.
However while these are satisfactory, many homes are supplied with a gas supply, either being reticulated or being supplied by storage cylinders and it is an object of this invention to provide a suitable instantaneous type gas domestic water heater.